Why does <!docType HTML> render as text/plain, in a .QMD file?

[beedell-roke]

Description

When I render discussions/14935#discussioncomment-18568454 to /HTML inside quarto preview $HOME/qmd.qmd --no-browser --no-watch-inputs, I observe that it is visible, which it surely should not be, as invisible HTML, in any CommonMark superset, should be invisible when rendered.

[mcanouil]

Could you make your question self-contained, with a small reproducible example?

The comment you link has no Quarto document in it, but your command renders qmd.qmd.
Please share that file, or a cut-down version that still shows the problem, along with your Quarto version.
I'm also not sure what you mean by "to /HTML".

Also, Quarto isn't a CommonMark superset, so that assumption won't hold.
Quarto 1 uses Pandoc's Markdown, which has its own rules for detecting raw HTML.
To avoid detection issues, put your HTML in a raw block, as already described in https://github.com/orgs/quarto-dev/discussions/14935:

```{=html}
<!DOCTYPE html>
...
```

Note that because of the partials/templates for HTML, all the HTML you placed in the body of a Quarto document won't end up in the correct place, they will all be inside <body>.

[beedell-roke]

Could you make your question self-contained, with a small reproducible example?

@mcanouil, it should be self-contained, for I am merely asking why <!docType HTML> renders as its source representation when rendered, rather than disappears, as one expects from a CommonMark-adherent parser. (That question already exists in the mere title!)

I'm also not sure what you mean by "to /HTML".

I am referring to IANA Media Types. They are the mechanism by which one identifies file formats.

Also, Quarto isn't a CommonMark superset, so that assumption won't hold.

What is it, then? That certainly was my assumption, so I am surprised. jgm/pandoc/blob/1c81b5196430aa7d520f990b13d45a6901e38802/MANUAL.txt#L6467-L6476 appeared to demonstrate so.

To avoid detection issues, put your HTML in a raw block

That would render it. I want it to not render, so that I am able to process an HTML file via Quarto.

---

Note that because of the partials/templates for HTML, all the HTML you placed in the body of a Quarto document won't end up in the correct place, they will all be inside .

Are you able to rephrase this? I am unfamiliar with the concept of partials, nor do I understand what shall be misplaced, where, and why. Apologies.

[mcanouil]

I cannot answer all your first comments, because I have no clue how to see what you see or are talking about.

Pandoc supporting several markups does not mean it's a superset of all of them.

Are you able to rephrase this? I am unfamiliar with the concept of partials, nor do I understand what shall be misplaced, where, and why. Apologies.

---
title: My title
format: html
---

BODY

will lead to:

...
<body>
...
BODY
...
</body>

So putting <!DOCTYPE html> even in raw HTML there will be invalid HTML because that's not something to place in <body>, but again I have no clue what you are going, as context is lacking as well as something fully reproducible.

A wild guess is that you are writing this as plain markup and expect Pandoc to read it as HTML even though it is clearly misplaced as it's in the body.

Regarding what partials/templates are, I'll let you read the documentation:

• https://quarto.org/docs/journals/templates.html

---

Side note: please do avoid pinging in every reply. This triggers louder notification than actually needed (there are also nobody else in this thread right now). Thank you.

[beedell-roke]

I cannot answer all your first comments, because I have no clue how to see what you see or are talking about.

• mdn/content/blob/HEAD/files/en-us/web/http/guides/mime_types/index.md elaborates on what media types are.

• I am attempting to ascertain why <!docType HTML> is visible in the rendered output of a QMD file, rather than pre-processed such that it is redacted. You correctly assume this later in your message.

---

Pandoc supporting several markups does not mean it's a superset of all of them.

Surely, depending upon its mode, it must be? I expected that because a QMD file's name refers to "Quarto Markdown" that it would be the Quarto superset of Markdown, whose standardisation body is CommonMark. Where have I gone wrong?

So putting <!DOCTYPE html> even in raw HTML there will be invalid HTML because that's not something to place in <body>, but again I have no clue what you are going, as context is lacking as well as something fully reproducible.

Indeed. Though, although the WHATWG may consider a stray docType to cause undefined behaviour, all browser engines, that I am familiar with (Gecko and Blink), merely hide it:

1. <!DOCTYPE html>
   <html lang="en-GB-oxendict">
   	<head>
   		<meta charset="utf-8">
   		<meta name="viewport" content="width=device-width, initial-scale=1">
   		<title>Title</title>
   	</head>
   	<body>
   		<!DOCTYPE html>
   		test
   	</body>
   </html>

2. 

---

please do avoid pinging in every reply.

I shall attempt to, but I speak to hundreds of people every week, and I've both always been advised to tag whomever I respond to, and would want anyone else to do the same, in case I am not subscribed to a thread. Consequently, please do not be surprised if I forgot that specifically you have asked otherwise.

[mcanouil]

Could you actually share your QMD file? My issue was never about the mime type, but about the fact that you shared nothing to allow anyone to reproduce/see what you see.

Again making wild guess of what you are doing.
Here is a markdown document (not a qmd):

```{=html}
<!DOCTYPE html>
```

BODY

<!DOCTYPE html>
```

Pandoc is not parsing <!DOCTYPE html> as HTML thus Quarto has no reason to do so in Quarto 1 since, Pandoc's reader is being used.

quarto pandoc --from markdown index.qmd --to html

<!DOCTYPE html>
<p>BODY</p>
<p>&lt;!DOCTYPE html&gt;</p>

Then still the question on why you'd write this in Quarto which will end up inside <body>.

And again, that is why ```{=html} is there to ensure HTML is treated as HTML.
Either use it to ensure your HTML is read as HTML, or keep facing weird issues by hoping all your HTML is guessed with the right language by Pandoc.

And when adding screenshots, please do add alt-text, or use plain text when screenshots don't show much more than text.

Important

Accessibility: To improve accessibility, please add alternative text to your screenshots. This helps all users, including those using screen readers, to understand the context of the images. A brief description can make a big difference! See Good Alt Text, Bad Alt Text — Making Your Content Perceivable.